Talk:Dobsonian telescope

Correction to article

This article seemed to incorrectly describes the "Dobsonian" as just a mount. The "Dobsonian" is actually an innovative telescope and mount design. I don’t know if this is because it was originaly a redirect from an article about mount types but I have edited it to be more descriptive of the entire class “Dobsonian”.(Halfblue 05:00, 10 March 2006 (UTC))

Merging telescope mount articles

Hello. I was browsing the various telescope mount articles recently (see Telescope mount, Altazimuth_mount, Equatorial mount, Dobsonian), and I'd like to propose merging them into a single Telescope mount article. Does anyone have any thoughts about this? If so, could you please visit Talk:Telescope_mount#What.27s_the_role_of_this_article and perhaps comment? Izogi 04:01, 18 July 2005 (UTC)

The "Dobsonian" article you are refering to was incorrect in that it describes the Dobsonian as just a mount style. The Dobsonian is a full telescope design encompassing the telescope and the mount.

"Dobsonian Mount"?

Is there such a thing as a Dobsonian Mount? The Dobsonian seems to be a class of telescope that uses a combination of previously know innovations for a specific design purpose (a large, cheap, portable, deep sky instrument). It may be a misnomer to call any one of those design features "Dobsonian". i.e. The Dobsonians do not have "Dobsonian Mounts"; they have Altazimuth_mounts. And those Altazimuth_mounts may use John Dobson's design features but that would make them "Dobsonian style" Altazimuth_mounts. I have made a few minor text changes to this end but would appreciate other people’s opinions. Halfblue 05:16, 21 March 2006 (UTC)

Well, there isn't really any such thing as a "Dobsonian telescope" - I was about to mention that here. The telescope is a normal Newtonian. The characteristic feature is the mount. You're correct that it is an Alt-Az but that doesn't mean that it isn't also a Dob - witness equatorial mounts where you have German, horseshoe and fork (+wedge) mounts amongst others. These are all equatorial mounts but they are also their distinct subcategories. Same is true of a Dobsonian mount only it is an Alt-Az mount rather than equatorial. CrispMuncher (talk) 11:28, 14 July 2008 (UTC)

Cleanup

I cleaned up the edit up to 01:32, 27 September 2006. Sections of it seemed to just describe commercial types instead of Dobsonian evolutions and also read as a "how to" Buyers guide WP:NOT. "Truss Tube” was not "invented" in 1989 so need to more specificaly describe it as an evolution. Uncited claims such as "rigorous documentation to ensure their optical quality to the purchaser", "better distribute the mirror box’s weight", and whole sections on current commercial models seem to be derived from ads and are therefor POV. RV'ed whole sections on "two generations" of Dobs since that doesn’t seem to be substantiated by sourced material. The rest of the changes are very good IMHO and I have simple re-arranged some of them to be more encyclopedic. (PS there are GFDL images of “Truss Tube” Dobsonians on Wikipedia Commons in case the immage supplied gets afD'ed. Will leave current image for now so its editor can supply a Copyright rational.) Halfblue 19:17, 27 September 2006 (UTC)

Re-Cleanup

Dear Halfblue. Thank you for comments – it’s great to see that there are others interested in this article. I do disagree with you in many, many areas and I feel a few of your comments are quite subjective and POV (e.g. what constitutes “factual” and encyclopedic) but I’m hoping we can work together to refine this article. The original article was a good start, but as an amateur with 30 years of experience, I feel that it had a very narrow breadth (focusing primarily on ATM’s) and does not encompass the full history or important aspects of this design. Here are the major area’s I disagree with you on:

• First of all, I’m sensing a bias POV against “commercial” telescope manufacturers as engendered by your concern that the last edit “describes commercial adaptations instead of describing the designs in the amateur telescope making world where Dobsonians were really developed”. Please bear in mind these designs were greatly improved on popularized by commercial makers (many of whom started as ATM’s). Most Dobs are bought, which make manufacturers highly relevant. Some manufacturers, such as Coulter (e.g the “Volkswagon” of Dobs) and Obsession (which made the truss design popular) greatly changes the overall evolution of this design, and deserve mention.
• Second, I complete disagree with your characterization that this is somehow a “How To” buyers guide. Again, I’m sensing a bias against the discussion of anything commercial. An authorative article on cars would likely mention the larger makers, and price ranges of typical model – it’s factually relevant to anyone trying to get an understanding of the subject. The mere mention of a manufacturer does not mean its advertising. The discussion of the differences of each type is no more of a buyer's guide than the pro's/con's section that existed earlier. There’s nothing wrong with it or counter to Wikipedia’s policies.
• Truss Tubes are a very distinct and popular telescope, and deserve a separate category. I earlier proposed “first” and “second” generation scopes, but perhaps the categories “classic” and “truss tube” may be better. Commercial truss designs have been in their current form for 15+ years. Having observed in California in the past 15 years I know that they’ve become the dominant scope by number at star parties, much in the same way C-8’s were 20 years ago. I don’t feel that “Continued Evolution of the Design” is adequate – this a definite sub category recognized by most sources (e.g S&T, Astronomy, Etc.)
• I made no claim that the Truss Tube was invented in 1989, only that the first commercial models became available then, so I left this part in. I’ve modified it though to pay homage to the ATM’s that likely developed this contribution.
• I’ve worked on some of the language your earlier took issue with (e.g “premium optics” and better weight distribution)

I’ve restored much of the content modified in respect to your earlier comments. Please, let’s work together in developing sources and refinements. Let’s not simply delete content wholesale because one of us happens to disagree with it. Again, bear in mind that I’m writing this as a amateur astronomer with 30 years experience who has himself taught classes on the subject. I have no vested commercial interested in any particular telescope or manufacturer. Joeconsumer 09/27/06.

Well... speaking as an amateur and professional telescope maker with a 35 year history I have to say... the article looks better, needs work, but looks better. When I talk about "encyclopedic" I mean that encyclopedic articles describe "things". The thing in question is a "design" so the article should describe the design, its origins, and its evolution, relevant additions ect. I have seen other articles where people want to describe a "design" via commercial models that are available. Commercial models may have their place but they are more a response to a market than a relevant landmark in a design. None of the innovations you attribute to commercial manufacturers are in fact "innovations". They all were in full swing well before some company picked them up. The Truss Tube existed way before the advent of the Dobsonian let alone its adaptation by manufacturers. And it was in full use practically in "first generation" dobsonians (have a look at my picture on the Amateur telescope making page and you will see Truss Tube Dobsonians lurking in the background in 1981). And when a manufacturer does pick up a design it lags the actual evolution... for example there is a greater than 20 year gap between the origin of the Dobsonian and the first Coulters. Commercial designs follow markets and tastes... so they are minimally relevant on a page about a design.

Have a look at "cars". "An authorative article on cars" does not "mention the larger makers, and price ranges of typical model"... in so much as it lists landmarks in its evolution and commercial companies contribution to that evolution.

That's why I changed "Second Generation “Truss Tube” Dobsonians" to "Continued evolution of the design". There is no hard cutoff like you tried to characterize in your first edit. And the prevalence of commercial truss tube Dobs today are not a continuing evolution as much as a few commercial manufacturers' response to a market <--- and that gives you a sub-heading "Commercial applications".

Working together on this is a good thing and Wikipedia recommends it for a good reason. Whacking the revert button may not be the best way to do that so I put forward my reasons and views...make what you will of them. Halfblue 04:46, 28 September 2006 (UTC)

Hi True Blue: Thanks, I agree that there’s a lot that can be done to improve the overall article. Here are my thoughts going forward.

• Add more ATM History: I’ve mostly bought my scopes over the years, so I’m not as well versed in the contributions of ATM’s outside of John Dobson. Clearly this group developed a lot of the major innovations so I think we should develop their history more.
• Don’t downplay the importance of manufacturers: They are important – many of us would not have dobs if it wasn’t for the Coulters and Orions of the world. Going back the car analogy, like ATM's many innovators came up with the fundamental construct of the modern car by the early 1890’s, but it didn’t really become wide spread until Ford produced the Model T – and historically, that’s very relevant. Sure there are the “consumer” driven Meade and Celestrons of the world, but remember that many other smaller companiies (Obsession, Discovery, Starsplitters) started off as ATM’s that simply decided to sell their wares.
• Add evolution section / other relevant subcategories: I believe that we should have a separate category for truss tubes, but there’s noting precluding the addition of another category discussing ongoing evolution or some of the other new types of scopes. I seen many ATM’s use monopole supports instead of a Verrier Truss. The “portoball” type of instrument is a good variation. I’ve seen many ATM’s (and at least one commercial outfit) experiment with collapsible carbon fiber design – which could have important implications in the future.
• Add more references / citations: I admit there is a lot of sources we should add. We could start adding “citation needed” marks and begin the process of locating the references

My thoughts for now... Please don’t let me discourage you from making tweaks /edits to the article. I’ll probably have a bit more time to work on this over the coming weekend. JoeConsumer 06:34, 28 September 2006 (UTC

The Show So Far

All those mods you mention would be a good idea. I have made some more basic mods that may address some of what you mention. They will help categorize any additions to come. I find that you can always find help on Wikipedia its self. On of the first pieces of advice in article writing is What are you (we) trying to say? What we are trying to say is “There is a design, it has these applications, it has had these derivations”. In polishing up a quite a few articles on telescopes I have come across other peoples examples of organizing this type of information. The one I think will help here is Schmidt camera. I am making changes based on that. One line of thinking I am working along is that the "Dobsonian" is getting to be a historical artifact... the creation of one mind or group. So it should probably be discribed as a single or "classic" invention that then has derivations.

So:

• Introduction (Wikipedia asks that this be short and sweet… hitting just the most relevant highlights) Some edits made there... mostly moves to more relevant sections.
• Invention and Design. (Covered pretty well)
• Applications ((Old article has that but this shows me that Advantages and Disadvantages needs to be moved up and needs to be made a sub heading)
• Derivative Designs (this is where information on amateur and commercial adaptations belongs. And those adaptations should be described in reference to the original design or concept.)

Material has been pretty muched re-arranged into their logical sections These edits continue to follow this philosophy:

• Get it all in order. Avoid describing the design backwards. It needs to be A-B-C-D instead of trying to describe it from what we see today and working backwards. Get all information into their logical sub headings.
• Dig!!! Describe variations RE: where they came from (Wikipedia asks for citations when possible) errr… this may be hard since its seldom that one single person can or will step forward and say “I invented the rocker box mount”. But even superficial “digging” shows me that most design variations we are talking about here were not invented by commercial interests.
• Describe. Describe what the variations are, where they came from, and why an amateur or company used them.

Halfblue 16:51, 29 September 2006 (UTC)

objectionable?

I have rm'ed the following to talk since it is unreferenced and therefor WP:NPOV. Could be re-added if there is reference to someone actually saying this. Fountains of Bryn Mawr (talk) 23:09, 23 February 2009 (UTC)

The term "Dobsonian" is considered objectionable by some purists since the Dobsonian telescopes are just Newtonian reflectors with a simplified mechanical design. Normally, proper names for telescope designs are associated with the optics (Cassegrain, Maksutov, Ritchey-Chretien etc.) and not with with the way in which the optics are mounted.

I put it back. The second sentence is quite correct; do you know of any exceptions? And as a long-term amateur astronomer, I can attest to the accuracy of the first sentence.IrishFilmBuff (talk) 09:54, 24 February 2009 (UTC)

We usually don't add more unreferenced opinion to an article just because other stuff exists. The description part of the first sentence is redundant to the intro and .... "considered objectionable by some purists"? --- who?WP:V. You may be able to "attest" but we can't go by that WP:OR. And there are exceptions of telescopes named after the way they function such as Solar telescope, Turret Telescope[1], springfield telescope[2]. The best we can say is that "Dobsonian" describes a newtonian of a specific mechanical design, and i think that is stated in the intro already, although we could say "The term "Dobsonian" or "Dob" refers to a specific mechanical design for a telescope with an alt-azimuth mount and a Newtonian telescope tube assembly that feature several innovations made popular by John Dobson." Fountains of Bryn Mawr (talk) 13:48, 24 February 2009 (UTC)

Biased!

I certainly agree with whomever added the "peacock" label. This article is terribly biased. Dobsonian telescopes sacrifice everything for the sake of large aperture. They are a huge step backwards in almost every respect but size. A person who learns about Dobsonians from this article would get a totally wrong impression.JBHarshaw (talk) 11:55, 25 February 2009 (UTC)

Peacock

I made some changes in the opening paragraph to lessen the "peacock" nature of this article.UMinnAstro (talk) 12:28, 25 February 2009 (UTC)

I have done a partial revert of the additions made re:Peacock because the additions made had no references. The way to correct "unqualified opinion" is not simply adding more or counter unqualified opinion. The article does need cleanup but additions/changes should be neutral and help describe a dobsonian telescope, not render opinion on it. I also note that a whole series of very similar edits have been made from accounts with equally similar recent creation dates. May just be a coincidence, otherwise a reading of WP:SOCK is in order. Fountains of Bryn Mawr (talk) 22:09, 25 February 2009 (UTC)

So that everyone understands where I'm coming from I'll make my own personal position on Dobs clear at the outset:

1. I don't like them.
2. They're cheap.
3. They make some things that should be easy difficult.
4. They are not best suited to planetary work.
5. Contrary to the assertions of many Dob advocates, they are not all things to all people.
6. They are however often the only way of gaining aperture affordably.
7. They are also easy for ATMs to construct.
8. They also have a certain amount of convenience, in that there are no alignment issues to worry about.

With the exception of 1) which is of course entirely my POV I believe I can find extensive reliable sources for all of those assertions and I believe them to be fair and balanced. The primary advantage of a Dob is the price tag, which allows larger aperture and/or better quality for a given budget. I don't believe that is particularly controversial. However, compromises are made for that advantage. We need to be careful to ensure that this article is balanced. Yes, if we are to assert that that "by definition" the primary is poor quality we need to be able to cite that definition. I think you would struggle to find such a definition, though, and in any case it would be disproved by e.g. Obsessions where the mirrors are first rate.

On the flip side, we also need to avoid over-promoting the configuration. This is particularly true of the planetary claim - pretty much any reliable source advises against Newts in particular and reflectors in general for planetary. Yes, you can use them and use them effectively, but I doubt you will find many experts who would recommend them over a good refractor.

In summary, I am on neither side of the constant edit-warring that has affected this article over the last few days. I think all parties need to examine their motives and moderate their statements. Dobs are not a panacea nor are they abominations. In other words we need to restore a sense of balance. CrispMuncher (talk) 19:12, 26 February 2009 (UTC).

I think the article has gone through some changes in the past, based on the old talk above and history that have made it the way it is. It seems to have gone from a basic description of the original design (though unreferenced) and then got added onto by an editor who was describing the newer commercial types, probably from first had observation and by quoting ad copy. I think some of the additions as of late have been illogical, for example: any telescope will have a crummy mirror if you install crummy mirror, this is not a "feature" of the Dobsonian. Any telescope can be used for planetary work; it’s not a feature. All designs have advantages and drawbacks. Now allot of the refs show the authors noting how poor the optics were on the Dobsonians they observed, but anecdotal observation or even opinion should be cited as such (see: WP:SOURCES WP:NPOV) re: "Author XXXX noted Dobsonians built by YYYYYY have poor optics". Poor optics probably have allot of reasons: people making "light buckets" on purpose, people tackling very big mirrors the can't properly figure because "hey... I can now have an f'ing big mirror!!!", Portholes that are poorly annealed/warped because they were never intended to be optical surfaces, etc. All in all I think we should refrain from inserting any opinion at all on Dobsonians, that is not our job. We are an encyclopedia so we describe, we do not pass judgment or give advice by definition and consensus. A section on the "quality" and usage of Dobsonians in the amateur community could be added but there would have to be overwhelming notability of such published sentiment. As far as sides in an edit-warring, I suspect that the "sides" were manufactured as was most of the "war", something that is being dealt with. Fountains of Bryn Mawr (talk) 20:40, 26 February 2009 (UTC)

"By definition..."

Concerning the edit summary comment: "BY DEFINITION, Dobsonians have lower-quality mirrors than ordinary reflectors[3]: I have an 8" pyrex blank sitting under the piano that I hope to start grinding before too long. By your definition I am prohibited from placing it in a dobsonian structure if I manage to polish too fine a figure??? That is preposterous on its face. --Kbh3^rdtalk 23:50, 25 February 2009 (UTC)

By definition redux

I have re-edited the page based on the only objectified description of a Dobsonian telescope's optical performance characteristics---> they are newtonian telescopes. Since the optics in a dobsonian run the same gamit from good to bad as found in any other amateur or commercial telescope they really have no other definition optically. Their mounts have a similar definition---> they are Altazimuth mounts. rm'ed some redundancy as well as text that does not fit the definitions above. Fountains of Bryn Mawr (talk) 00:47, 11 March 2009 (UTC)

Reversion of edits by 75.198.110.119

I have again reverted the edits by the above IP. Editing the "original" Dob section to the present tense makes this section less clear. The whole purpose of that section is that it is talking about a small number of specific telescopes made in the past. It also confuses the distinctive characteristics of the "original" scopes with all Dobs. I am pretty sure that 99% of Dobs made today do not use porthole mirrors. Similarly a truss Dob is still a Dob even though is is not made of Sonotube. Rewriting this section in the present tense confuses those Dobs with present Dobs and disrupts the logical flow of the article CrispMuncher (talk) 16:21, 20 March 2009 (UTC).

Did a cleanup for tenses, style, redundancy, and a general "what are we talking about?". In an encyclopedia Things, such as a design of a telescope, Sonotubes, etc are present tense re: "Newtonian telescope is a type of reflecting telescope". Hard tube dobs are not made in the past, they are still built. Past events of a living person are "past tense" (WP:MOSBIO). I see no reference that dobsonians have any clear "classic", "hard tube" or "first generation" form. "present dobs" are all styles, there is no one "present" design or even past design since every one is a built to suit the user or manufacturer. Fountains of Bryn Mawr (talk) 23:27, 26 March 2009 (UTC)

Yes, modern Dobs are all different, which is why we need to draw a distinction between the two senses of Dob: the particular scopes built by Dobson and the derivative designs produced since. The old revision of this article did this very well - it covered the Dobs made by Dobson under the "original" moniker and then went on to show how the design had evolved. The present revision presents this as a "big bang" revolution in telescope design where both the true Dobsonian characteristics and the subsequent eveolution to the design are presented together. That removes contxt from the article as does not show how the design has evolved over time, as you correctly point out, to suit the requirements of the builder or owner.

Additionally, I think the portability arguments are overplayed in this revision. For a start it is not universally accepted that a Dob is more portabel than e.g. a GEM. However the coverage of the "requirement" of travelling to a dark sky is completely at odds with Dobson's promotion of sidewalk astronomy, to the extent that he is frequently described as the pioneer of the movement. Sidewalk astronomy is obviously not abotu specifically travelling to dark sky locations. Most source I have seen attrubute the deign of the Dob to a desire to constrcut it at low cost and from readily available materials. Portability was a secondary consideration. CrispMuncher (talk) 18:26, 3 April 2009 (UTC).

It boils down to is there any such animal as a "modern Dob"? That notion is sort of shot out of the water by simply looking at the photographs in this article and in Amateur telescope making. You can see very clearly collapsible and truss tube dobsonian and other style telescopes lurking in those pictures from the early 80's. And the pictures in the April 1989 Smithsonian Magazine show Dobson and the San Francisco Sidewalk Astronomers building all styles of "dobsonians". So they don't seem to have some fixed "classic" design. And what denotes a "modern Dob"? The fact that Ivar Hamberg added wingnuts to the truss design? Even if that were true but we need verifiability, not truth. That is why I rewrote the section to "Dobson's design innovations". Dobson put forward a series of innovations that have all be lumped under "dobsonian", but it is a design idea, not a fixed in stone single design you can call "classic".

Dobsonian portability seems to be well referenced[4][5]. Portability was a given for the purposes of a "monk on the run". The GEM mount for a 16-24 inch telescope is usually way to massive for any one person to move, let alone the OTA. And setting up on a literal "sidewalk" needs a very compact and portable telescope - even more so than setting up in say, Grand Canyon National Park. There are many accounts in the references provided about the "San Francisco Sidewalk Astronomers" setting up at national parks as well as "sidewalks". "Sidewalk" seems to be a euphemism for bringing astronomy to the people more than where they do all their business. Fountains of Bryn Mawr (talk) 16:39, 5 April 2009 (UTC)

Reversion of edits by Fountains of Bryn Marr

User 74.42.36.182 raises a very interesting issue that we have often discussed at the Vancouver Sidewalk Astronomers (VSAs): What is a Dobsonian? Our group has several Dobs. We also have one vintage (ca. 1940) 16 inch Newtonian reflector on an alt-azimuth mount. The younger VSA members insist on calling that telescope a "Dobsonian", but I never tire of explaining to the young-uns that it was built decades before John Dobson arrived on the amateur astronomy scene. When I read old astronomy books and magazines, I see pictures of telescopes that would nowadays be called "Dobsonians" -- but they all pre-date John Dobson. So what, exactly, makes a telescope a "Dobsonian"?

Here are some things that are NOT specific to Dobsonians:

• Optical design. Dobson used a standard Newtonian optical train.
• Mounting. Fork-mounted alt-azimuths have been around, like, forever. (Russell Porter? How about Lord Rosse? William Herschel? etc.)
• Large aperture. At my very first star party (1962) I distinctly recall a 20" truck-mounted reflector.
• Innovative materials -- cardboard tubes, wooden bases, makeshift bearings -- all were in use around the time that I got started in the early 1960's. Cash-strapped amateurs have been finding innovative ways to use common materials since the earliest days. My first reflector made liberal use of parts from an auto junk yard.

Even the specific combination of elements is not unique to John Dobson. If you don't believe me, take a look at Sam Brown's pamphlets on telescope making from the 1950's (published by Edmund Scientific) -- you will find designs for telescopes that contain all of John Dobson's supposed innovations. But, they are not called "Dobsonians", because Dobsonians had not been invented yet.

Still, most amateur astronomers seem to have something definite in mind when they talk about "Dobsonians". What, exactly, is that, and how does it differ from what came before? That is a key question which this article needs to address, and this is why I undid Fountains_of_Bryn_Mawr's deletions. I have also added a link to an article that cites Dobson's own definition of a "Dobsonian".67.208.5.162 (talk) 16:35, 2 August 2010 (UTC)

You expanded on a series of unverified and probably untrue statements, I have rm'ed those first two sentences (see "objectionable?" talk above). Also lead sections are for summarizing articles (WP:LEAD) so I have reworded the rest to fit that guideline. Fountains of Bryn Mawr (talk) 20:46, 2 August 2010 (UTC)

The issue here is what distinguishes Dobsonians from other things -- i.e., why is there a separate class, and name, for these telescopes. This deserves discussion right at the start of the article. I've also removed the fatuous sentence about the "design continuing to evolve". The more the design evolves, the more it looks just like pre-Dobsonian telescopes, since commercial dealers and serious amateurs are doing away with the crude construction techniques that are the sole defining element of Dobsonians.67.208.5.162 (talk) 13:29, 6 August 2010 (UTC)

Thank you for your edit, it has been reverted. The opinion that "crude construction techniques" is the "defining element of Dobsonian" can not be the basis for additions to an article per WP:NPOV. Other additions must pass WP:PROVEIT and again not be opinion. Fountains of Bryn Mawr (talk) 17:09, 9 August 2010 (UTC)

Hmmm...Fountains, I've spent some time going over your edit history. You seem to have a penchant for imposing your personal point of view on otherwise balanced articles, and invoking one or another of WP's many policies to justify your biased point of view. I'm on to you! 67.208.5.162 (talk) 22:44, 25 September 2010 (UTC)

Sorry you have that opinion and feel the need to ignore Wikipedia policies and guidelines, such as not making personal comments on talk pages. You may be more happy in another project where you can actually express (impose?) your own opinions. Fountains of Bryn Mawr (talk) 03:04, 26 September 2010 (UTC)

POV "Dobsonian definition"

This talk page (and these SPI and ANI reports[6][7]) show a high number of edits from differing anonymous IP addresses and identified sock-puppet accounts that all probably belong to one user. If you have been referred to this talk after restoring one of these edits you should provide reliable sources before restoring and maybe consider creating an account[8]. Fountains of Bryn Mawr (talk) 17:09, 28 September 2010 (UTC)

Don't know what a "sock-puppet" is but I'm pretty sure I'm not one. I restored the deleted paragraph. It is supported by two good references. If you are going to delete it yet again, please give a bona-fide reason. 67.208.5.162 (talk) 20:53, 1 October 2010 (UTC)

The reason is WP:PROVIT, as bona-fide as it gets. The first two statements[9] are unreferenced (WP:V). The rest is redundant refactoring of material already in the article. Fountains of Bryn Mawr (talk) 04:03, 2 October 2010 (UTC)

The sentences are now referenced. Please don't delete this paragraph yet again; doing so violates WP:NPOV. 67.208.5.162 (talk) 19:42, 3 October 2010 (UTC)

I have added yet another reference. I hope that this one meets your exacting standards. 67.208.5.162 (talk) 12:21, 4 October 2010 (UTC)

The standard you should be adhering to in not mine, its Wikipedia's, namely Wikipedia is not a publisher of original thought. The claim that "Dobsonians" exceed a "rule" is not supported (that has to be someone else's thought, not yours). New ref only cites that there are optical types with specific names, not that there is a "rule" or that there can't be other types (which there are[10]). Rest is still redundant (not addressed at all). reverted. Fountains of Bryn Mawr (talk) 20:26, 4 October 2010 (UTC)

There you go again: Invoking a new reason each time for reverting my edit. What remains constant is your determination to keep this article from being improved. I think it is time to take this to a higher authority. 67.208.5.162 (talk) 00:40, 7 October 2010 (UTC)

Possibility of thinner mirrors needs clarification

Among the advantages outlined for the Dobsonian, the article says:

Since the telescope design has an alt-azimuth mount the mirror only has to be supported in a simple cell with a backing of indoor/outdoor carpet to evenly support the weight of the much thinner mirror.

I'm afraid I don't follow that. Might one not be just as apt to point a Dobsonian in any direction that you might point a typical Newtonian scope with equatorial mount? So the mirror would have the same strains. If it has to do with the box that holds the mirror, is there any reason not to put that box in a typical Newtonian scope with equatorial mount? Uporządnicki (talk) 18:10, 20 August 2015 (UTC)

Its not where you point it, its the orientation the tube ends up in. People who use EQ mounted newtonians almost immediately hit the situation where "damn, the eyepiece mount is upside down!!!". An EQ mount can orientate the optical tube (and the mirror) at an infinite number of angles and even upside down, meaning you need a complicated cell that can support the mirror at all orientations. The basic dobsonian design only tilts in one plain, 90% to 0%, so you only need to support the mirror back and one side, usually with some form of cradle or strap along that edge. Fountains of Bryn Mawr (talk) 19:32, 20 August 2015 (UTC)

NEW CORRECTION BY A TOTALLY DIFFERENT USER

I cant figure out how to use wikipedia to properly edit the article. The Orion 50 inch dobsonian was never produced, it was a market test. http://www.cloudynights.com/topic/323598-orion-monster-dobs-not-happening/ They made a 36 inch which had some apparent problems, the offered 42 and 50 inchers were never even made as a test.

The largest Dobsonian actually produced and sold commercially to my knowledge is a 36 inch by Obsession which is no longer available either, although other makers have said they would consider making 36 and 40 inch scopes.

Also the largest homebuilt dobsonian scope is currently a http://www.davidreneke.com/the-worlds-largest-amateur-telescope/ 70 inch still being completed. It is not in this list of other largest scopes which are probably all dobsonians. http://www.bbastrodesigns.com/Largest%20Amateur%20Telescopes.html — Preceding unsigned comment added by 75.168.128.95 (talk) 20:04, 8 July 2016 (UTC)

The sources are kind of thin as far as Wikipedia goes, blogs/personal websites/message boards are not considered very usable. The article itself is not much better so this could be added in some way. Fountains of Bryn Mawr (talk) 21:22, 8 July 2016 (UTC)

External links modified

Hello fellow Wikipedians,

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Commercial adaptations

If no objection, I propose to remove the "largest commercially available... 50-inch aperture", since Orion never did produce that years ago. Also plan to update that section with some newer information. (No, I am not a Dob seller :-) Assambrew (talk) 22:32, 18 June 2020 (UTC)

Sounds good to me. Fountains of Bryn Mawr (talk) 22:41, 18 June 2020 (UTC)

Thanks, that was quick. I'll get to it soon. Assambrew (talk) 03:49, 19 June 2020 (UTC)

Last time I really looked at commercial dobs they were Coulters ;) Now days when I do astronomy events I am surrounded by 21-24 inch goto monsters. Good for someone to update the commercial end. Fountains of Bryn Mawr (talk) 15:38, 19 June 2020 (UTC)

I had a Coulter Odyssey 8 myself back in the day. Okay, first change I made was to replace the mini-Dob photo with an example of a truss Dobsonian. Hope I did the fair use image stuff right, rather new to that stuff. Still working on the text, I will summarize changes here. Assambrew (talk) 23:59, 21 June 2020 (UTC)

Done. I made substantial revisions while keeping the basic outline. Much of the original section was unreferenced. Some of that text remains, with added refs. I listed refs for many commercial Dob makers (articles and reviews). Removed obsolete ref to Orion 50 inch model that never happened, and added a 50 inch scope that was actually delivered last year. Assambrew (talk) 07:14, 22 June 2020 (UTC)